1. Field of the Invention
The present invention relates to a panel with laterally mounted interlocking elements. The invention relates to a covering made of these panels, a method for its production and an associated apparatus.
2. Related Art
A panel is a plate provided with interlocking elements on its sides. The interlocking elements are designed for the positive interlocking of two panels, for instance at least at right angles to the plate surface. Preferred is the added positive interlocking between panels parallel to the surface and at right angles to the joint between two joined panels. In view of their positive interlocking effect, such interlocking elements are also referred to as positive locking elements. Such panels are described in EP 0 855 482 B1 or EP 0 698 162 B1.
The panels can be assembled to form a covering, lining or the like, in particular a floor covering or the like. The result is a covering based on laterally adjacent panels made of wood or timber, in particular based on wood or timber (decorative) laminate panels with lateral positive locking elements, possibly designed for click-in or snap-in mutual engagement, in particular tongue and groove, supported by bonding, with a lower base layer and a visible wear layer. The invention therefore relates to the panels with positive locking elements used for assembling coverings, linings or the like, to the production of a preferred panel assembly and to an apparatus for the production of the panels.
A great number of planar individual elements with lateral positive locking elements, in particular tongue-and-groove designs, is known. These planar individual elements may be boards, plates, panels, fillets or the like and can be assembled to form planar structures of any size and for a great variety of applications, such as linings for walls, ceilings and in particular floors. This applies particularly to floor coverings, where this technology has been used for a long time for wooden parquet floors. Plates, boards, panels or the like capable of being assembled to form floor coverings, in particular timber laminate panels or the like, require an aesthetically pleasing appearance, a good surface finish and hardness, a high abrasion and wear resistance of their wear layer and in particular a very stable bond, if the individual elements, such as panels, are joined by tongue-and-groove positive locking elements to form a (floor) covering. This applies to various types of loading and particularly to floor coverings. In the case of floor coverings, any tendency of the surfaces assembled from the panels to disintegrate into the original individual panels must be prevented for the entire service live of the covering or floor covering even if subjected to the hardest possible conditions of use.
With regard to the loading mentioned above, this may, for instance, be high and irregularly fluctuating, often substantially point loads, such as those caused by furniture legs, high-heeled shoes or the like on the base, or else movable loads, such as those caused by office containers with castors, wheelchairs or the like.
As has been mentioned briefly, panels or the like made of timber impregnated with heat-cured resin, consisting of a thicker carrier or base layer and an upper, usually relatively thinner but hard, wear-resistant and aesthetically pleasing surface or decorative layer, usually made of paper finally impregnated with heat-cured resin, i.e. timber laminate panels, have been used extensively for floor coverings for a long time.
In order to obtain the above-mentioned high mechanical stability of the tongue-and-groove panels making up a complete covering surface, in particular a floor surface, which is considered to be an essential specification, fresh glue or adhesive has been applied to the grooves and/or tongues of the panels in question before their installation for quite some time. Frequent problems were caused by the fact that a new panel had to be fitted within a relatively short time to form a tongue-and-groove joint with an already installed panel, the joint gaps between the panels having to be reduced to a minimum and—if possible—to near invisibility by lateral force, for instance by knocking or hammering.
A substantial problem has always been posed by manual and hence uneven glue application at the point of use, i.e. while the panels were being laid, and by the control of the quantity of the glue to be applied. If this quantity was insufficient in any surface unit of groove and/or tongue, the quality of the bond was affected and its durability placed at risk. If, on the other hand, too much glue was used, which occurred much more often for obvious reasons, the surplus glue had to be displaced through and from the gaps between the panels to permit their proper assembly, which became more difficult as the time between the application of the glue and the assembly of the panels increased. The result was that the gaps, even after being subjected to high and intensive lateral forces when “knocking together” the panels, remained too wide and thus did no longer disappear from sight. Another drawback was that the glue emerging from the gaps between the panels spread over the decorative surface of the covering at least near the gaps, thus contaminating the surface. While joining the panels, an operation which in itself requires a lot of attention, it therefore had to be ensured that the glue emerging from the gaps was removed, for instance wiped off, as soon as possible after the application of glue and the assembly of the panels, so that it could not dry out. If the glue was wiped off even a little too late, stains remained on the floor covering, affecting the optical properties of the decorative surface, for instance by being glossier that the rest of the panel or covering; this could have a bad effect on is appearance under certain circumstances.
DE 297 03 962 U1 suggests the application of an adhesive capable of transition from a passive to an active state on the sides of panels of the type mentioned above. Owing to the fact that there are no concrete embodiments, the suggested invention cannot be implemented by the expert. A suitable invention therefore has yet to be completed or published.